1. Field of the Invention
The present invention relates generally to telecommunications systems and more particularly to an improved system for detecting, analyzing and preventing fraudulent use of telephone calling card numbers. The invention provides enhanced intelligence and efficiency in detecting fraudulent use of calling card numbers and may therefore assist a telephone company in better identifying and responding to calling card fraud.
2. Description of the Prior Art
Telephone fraud is a major area of abuse in the United States and throughout the world. Such fraud frequently involves the unauthorized or bogus use of telephone billing numbers, which have been assigned to customers and are associated with customer billing accounts. These numbers are typically imprinted or encoded on wallet sized cards, which are provided to customers to enable the customers to easily charge calls to their respective billing accounts. Consequently, these numbers are commonly referred to as telephone calling card numbers. As those of ordinary skill in the art will appreciate, however, the terms "calling card number," "billing number" and "bill number" are not restricted to card-based numbers but may refer more generally to any number used to bill or track telecommunications services.
The present invention may be used in the context of telecommunications networks generally, including, for example, the telephone network depicted and described in U.S. Pat. No. 5,602,906, issued on Feb. 11, 1997 in the name of Phelps, for a toll fraud detection system ("the Phelps patent.") The Phelps patent, which is assigned to the assignee of the present invention, is expressly incorporated herein by reference.
A typical telecommunications network includes telephone units interconnected to each other via central offices owned by local exchange carriers (LECs). These central offices are in turn interconnected to each other via network equipment owned by long distance service providers, or interexchange carriers (IXCs). The LEC provides local switches for receiving and forwarding calls placed to and from the interconnected telephone units as well as a tandem switch for passing calls between the local switches and the IXC. The IXC in turn commonly includes tandem switches designed to receive and forward calls to and from the LECs and from point to point throughout the IXC's long distance network.
In the United States, when a call is placed from a telephone unit, equipment in the LEC central office examines the originating and target phone numbers in order to determine the availability of the target phone and in order to properly handle and bill the call. For local calls, one or more switches in the central office routes the call from the originating phone to the target phone if the target phone is available.
For long distance calls made with a calling card, a user typically places an initial call to a calling card platform in order to input the user's card number and destination phone number. In many cases, this initial call is toll-free and may, for instance, take the form of a 1-800 (or 1-888) phone number. When the user dials a 1-800 number, LEC equipment first determines which interexchange carrier is designated to handle calls placed to that 1-800 number. This determination is typically made by passing a data message to a local signal transfer point (STP) in the LEC, which may query a database to find an associated IXC. In turn, after identifying the IXC, local equipment queries the long distance carrier to determine whether the carrier and its equipment is properly available to handle the call and whether the carrier agrees to handle the call. This query passes between signal transfer points in the form of a data message identifying information about the call such as the originating number, the target number, and the caller's billing number or calling card number.
IXC equipment examines this information to determine whether the call should be placed and, if so, which equipment or logic should handle the call. Upon receiving confirmation that the proper lines and switches are available along the call path from the originating phone through the target phone, the switches along the call path then complete the call.
In advanced telecommunications systems, interexchange carriers have seen a need to provide specialized services to meet diverse customer needs. In order to provide call handling services to meet these diverse needs, an interexchange carrier may include in each of its switches multiple "originating partitions" or "o-parts," which identify logic for handling calls or bill numbers of particular types. O-parts have typically been used to provide "virtual private networks" (VPNs), which define the IXC calling network available for specified bill types.
As an example, an IXC may provide multiple calling cards to a corporate customer for use by the corporation's employees. Calls made with these cards bear a bill type representing the corporate customer. Therefore, all of these calling cards may be associated with a specific o-part in the IXC's switches, and the o-part may identify logic such as a VPN in the IXC's switches for processing calls made with the cards. In this scenario, customers using these cards may or may not be aware that their calls are being handled in a special way by a virtual private network, depending on the design of the network.
As another example, interexchange carriers may sell long distance service to local exchange carriers or other companies throughout the country that act as apparent "long distance service providers" to callers. An LEC, for instance, may establish its "own" long distance service for its customers by arranging for an interexchange carrier to supply the service and providing its customers with calling cards. By arrangement with the IXC, these calling cards may be associated with an o-part in the IXC's switches that defines custom logic for processing calls made with the cards.
Fraudulent use of calling card numbers has evolved over the years and has unfortunately responded to telephone company detection efforts. More particularly, as interexchange carriers have developed new systems to detect and prevent fraud, criminals have developed new tactics for defeating those very detection schemes. In an early form, for instance, calling card fraud was detected by customers or long distance service providers who recognized the existence of unauthorized charges on customer billing statements. In response, interexchange carriers developed systems for monitoring records of completed calls, in search of aberrations or telltale signs of fraud. In turn, however, criminals developed methods of maximizing their fraudulent use of card numbers before the calls are completed. For example, organized groups of criminals have arranged to simultaneously or serially make multiple calls from phones across the country using a single stolen calling card number. As another example, criminals have used stolen card numbers to make expensive overseas calls that last many hours at a time and that evade detection until completed.
Calling card fraud has subjected interexchange carriers and others to financial loss, in part because the charges for such calls are frequently uncollectible. This is especially the case when unauthorized use is made of calling card numbers for placing international calls, because the interexchange carrier handling the call may have to transfer payments to the destination telephone company, even if the toll charge is uncollectible.
In addition, the existing methods and systems of fraud detection employed by interexchange carriers have been only partially successful. This is illustrated, for example, by the fact that some interexchange carriers will not place calls using a billing number to certain suspect countries. This scheme, of course, unfortunately prevents some legitimate billing number calls from going through to these countries.
Further, fraudulent use of calling card numbers issued by local exchange carriers or other "service providers" may not only affect the interexchange carrier that actually provides the service, but may also affect customer perception of the local company that issues the cards. In some circumstances, these companies may in turn suffer financial loss as a result of such calling card fraud.
A need therefore exists for a more efficient and intelligent system of calling card fraud detection.